1. Field of the Invention
The present invention relates to a thin film capacitor using a nickel (Ni) substrate as at least one electrode and a method of manufacturing such a thin film capacitor. Particularly, the present invention relates to a capacitor as use of controlling Electro Magnetic Interference (EMI) produced according to supply voltage fluctuation of Large Scale Integration (LSI), and moreover, relates to a thin film capacitor suitably used as a capacitor equipped on a print substrate as being buried or attached and a method of manufacturing such a thin film capacitor.
2. Description of the Related Art
Various methods of the related art have been proposed for preventing Electro Magnetic Interface (EMI) produced from integrated circuits such as Large Scale Integration (LSI). For example, in order to control EMI produced with supply voltage fluctuation of LSI, discrete capacitors of the related art are disposed on wiring which connects power supply and power supply terminals of integrated circuits.
With the recent size reduction of electronic equipment, a capacitor for such use is desirable to be thin-shaped and well arranged. Thus, as described in Japanese Patent Publication Nos. 2000-164460 and 2005-39282, and Japanese Unexamined Patent Publication No. 2003-526880, generally performed is a capacitor formed in an array in a thin film shape sheet and the sheet is attached directly to a surface of an interposer or a print substrate, or buried inside of an interposer or a print substrate. In addition, not limited to the use for controlling EMI produced with supply voltage fluctuation of LSI, a capacitor for the other use may be attached directly to a surface of an interposer or a print substrate, or buried inside of an interposer or a print substrate in the same way as described above.
Because a thickness of a dielectric layer is thin in a thin film capacitor for such use, materials with high relative dielectric constant are used for the dielectric layer to enhance a capacitance density of the dielectric layer. The materials with high relative dielectric constant are, for example, perovskite-type oxides represented as ABO3 by the general formula. The perovskite-type oxides are, for example, barium titanium oxide (BT), lead zirconium titanate (PZT), lead lanthanum zirconate titanate (PLZT), lead magnesium niobate (PMN), barium strontium titanate (BST), and the like. The perovskite-type oxides can be obtained by crystallizing a precursor with annealing. High temperature annealing can enhance the relative dielectric constant.